Rotor of a wind power installation

ABSTRACT

The journals of two vanes of the wind turbine are connected with one another by a connecting rod 26 for absorption of the centrifugal forces of the vanes. Bearings with spherical faces are arranged between the ends of the connecting rod and the journals. The connecting rod is prestressed with a tensile force by means of a tubular bushing which surrounds the rod and which cooperates with threaded rings on the rod to tension the rod.

The invention relates to a rotor of a wind power installation. Moreparticularly, this invention relates to the mounting of vanes on a rotorof a wind power installation.

Heretofore, various wind power installations have been known whichemploy rotors for generating power from the wind. Generally, the rotorshave been provided with vanes which are disposed to rotate about acommon axis of rotation. For example, it has been known to provide arotor with a pair of vanes which are offset by 180° from each other andwhich have axes inclined relative to a plane perpendicular to the axisof rotation of the rotor by an acute angle.

In such rotors, the vanes are exposed in operation to strong centrifugalforces, which are absorbed by the hub. The hub, therefore, must be ofcorrespondingly heavy construction. As a result, the hub is large,heavy, expensive and fluidically unfavorable as to wind flow.

The invention has as its objects the creation of a rotor of this kindwhose hub is relieved of these centrifugal forces and therefore can bebuilt smaller, lighter, and at lower cost.

It is another object of the invention to reduce the size of rotors forconverting wind energy.

It is another object of the invention to increase the lift of a rotorfor a wind power installation.

Briefly, the invention provides a rotor for a wind power installationwhich comprises a hub for rotation about an axis of rotation, at leastone pair of vanes disposed about the hub with each vane having an axisof rotation inclined relative to a plane perpendicular to the axis ofrotation of the hub and a pair of journals each of which rotatablyconnects the vane to the hub to permit rotation of the each vane aboutthe respective vane axis.

In accordance with the invention, the journals of both vanes areconnected with one another by a connecting rod perpendicular to the axisof rotation of the hub. In this respect, the connecting rod is securedbetween and to the journals in order to absorb centrifugal forces of thevanes during use. In addition, a spherical bearing is disposed betweeneach journal and a respective end of the connecting rod in order topermit rotation of each vane relative to the connecting rod.

During operation, the centrifugal forces of the two vanes are mutuallybalanced out by the connecting rod. Hence, the hub need absorb only theweight of the vanes and the force components of the wind power.

Preferably the connecting rod may be surrounded by a tubular bushing, bymeans of which the rod is prestressed by a tensile force. Thereby thelong-term strength of the connecting rod, which in operation, under theinfluence of gravity, is exposed to a pulsating load, is substantiallyincreased.

Further, the space between the connecting rod and the bushing maypreferably be provided with lubricating grease to protect againstcorrosion of the surface of the connecting rod, which would result in areduction of the long-term strength.

An especially favorable embodiment is obtained by providing theconnecting rod at its ends with threads on which threaded rings arescrewed to be supported via the inner rings of the bearings on the endsof the bushing.

The outer rings, cooperating with the inner rings of the bearings canthen preferably be supported on threaded rings which are screwed intothreaded bores formed in the journals.

The bearings may be cup bearings with spherical sliding faces of thebearing rings. It is understood, however, that correspondingantifriction bearings, so-called swivel-joint roller bearings, whichpermit an inclination of the axes, may be used in their place.

The invention will be explained with reference to a preferred embodimentillustrated schematically in the drawing.

FIG. 1 shows an overall view of a wind power installation with the rotoraccording to the invention;

FIG. 2, a detail from FIG. 1 with partial section, on a larger scale;

FIG. 3, section III--III from FIG. 2, and

FIG. 4, a section of a part of the hub from FIG. 2, enlarged again.

The wind power installation illustrated in FIG. 1 contains a mast 1which is secured in a base 2 and carries a cabin 3 in which a shaft 4 ofa rotor 5 is rotatably mounted. The cabin 3 in turn is rotatably mountedat the upper end of the mast 1, in such a way that the cabin 3 can beadjusted with respect to the wind direction.

Rotor 5 contains a hub 6, which is secured on the shaft 4 and in whichtwo vanes 7 are mounted for rotational adjustment by means of journals8. The vanes 7 are offset by 180° in the direction of rotation of therotor, that is, the axes of both lie in a plane passing through the axisof rotation 4'. At the same time the axes 7' of the vanes 7 are inclinedrelative to a plane E perpendicular to the axis of rotation 4' of therotor under an acute angle alpha of e.g. 4° in the sense of a sweepbackdirected against the wind direction.

Shaft 4, whose axis 4' forms the axis of rotation of rotor 5, is mountedin the cabin 3 in bearing blocks 10 and leads to a transmission 11, fromwhich a shaft (not shown) leads to an electric generator (not shown),which may be disposed e.g. in the base 2.

FIG. 2 shows hub 6 together with the end of the cabin 3 which is closerto rotor 5, on a larger scale and in section.

Hub 6 contains a cylindrical hollow central hub portion 13 which issecured to a flange 12 of shaft 4 and from which hollow tubular arms 14extend essentially in the direction of the axes 7' of the vanes 7. Thehub portion 13 is closed off by a cupola 15. In the arms 14, thejournals 8 are mounted by means of bearing surfaces 16, 17.

At the inner ends of the journals 8, sleeves 18 are fastened, which areprovided with gudgeons not visible in FIG. 2 but shown in FIGS. 3 and 4,at which engage rods 20, which lead (away) from an adjusting rod 21. Theadjusting rod is guided by means of a yoke plate 22 and guide rods 23,which at the same time prevent rotational displacement of the adjustingrod 21 relative to hub 6. The mounting of the rods 20 is sphericalbearings of the gudgeons 24 at the sleeves 18 and gudgeons 25 of theyoke plate 22 is shown in FIG. 3.

It is seen therefrom that by a movement of the adjusting rod 21 towardor away from hub 6 the vanes 7 can be rotated, whereby their angle ofattack relative to the wind direction can be adjusted or changed in thedesired manner.

FIG. 4 shows the central portion of hub 6 still further enlarged. As canbe seen from this figure, the ends of the journals 8--toward the axes ofrotation 4' of rotor 5--of the vanes 7 are connected with one another bya connecting rod 26 which is perpendicular to the axis of rotation 4' ofrotor 5. Between the ends of connecting rod 26 and the journals 8,bearings 27 are arranged, each having an inner ring 28 and an outer ring30, which are provided with the sperical faces 31 and 32.

As can further be seen from FIG. 4, the connecting rod 26 is surroundedby a tubular bushing 33, by means of which it is prestressed by atensile stress. The space 34 between the connecting rod 26 and thebushing 33 is filled with a lubricating grease protecting againstcorrosion.

To create the prestress force, the connecting rod 26 is provided at itsends with threads 35, 36 on which threaded rings 37, 38 are screwed, andwhich are supported by the inner rings 28 of the bearings 27 on the endsof the bushing 33.

The outer rings 30 cooperating with the inner rings 28 of the bearings27 faces are supported on threaded rings 40, which are screwed intothreaded bores 41 formed in the journals 8.

To create the tensile force by which the connecting rod 26 isprestressed, the latter is provided at one end with a threaded journal42, at which a tensioning device (not shown), e.g. a hydraulic one, canbe inserted, which braces itself agains the inner bearing ring 28. Afterthe creation of the prestress force, the threaded ring 38 can betightened and secured. After removal of the tensioning device, thethreaded journal 42 can be protected by a cap nut 43.

As has been mentioned, the cup bearing 27 with the sliding faces 31 and32 may be replaced by a so-called swivel-joint roller bearing havingbarrel-shaped rolling bodies which roll off on a spherical surface.

I claim:
 1. A rotor for a wind power installation comprisinga hub forrotation about an axis of rotation; at least one pair of vanes disposedabout said hub, each said vane having an axis inclined relative to aplane perpendicular to said axis of rotation; a pair of journals, eachsaid journal rotatably connecting a respective vane to said hub torotate about said respective van axis; a connecting rod perpendicular tosaid axis of rotation and secured between and to said journals to absorbcentrifugal forces thereof; a tubular bushing surrounding said rod andholding said rod under a prestressed tension force; and a pair ofspherical bearings, each said bearing being disposed between arespective journal and a respective end of said connecting rod to permitrotation of said vanes relative to said connecting rod.
 2. A rotor asset forth in claim 1 which further comprises lubricating grease betweensaid rod and said bushing.
 3. A rotor as set forth in clain 1 whereineach spherical bearing has an inner ring with a spherical surfaceengaging one end of said bushing and which further comprises a pair ofrings, each ring being threaded on a respective threaded end of said rodagainst a respective inner ring for prestressing of said rod.
 4. A rotoras set forth in claim 3 wherein each spherical bearing has an outer ringslidably receiving a respective inner ring and which further comprises apair of threaded rings, each said threaded ring being threaded into arespective journal.
 5. A rotor as set forth in claim 1 wherein eachbearing is a cup bearing having a pair of rings with opposed sphericalsliding surfaces.
 6. A rotor for a wind power installation comprisingahub for rotation about an axis of rotation; at least one pair of vanesdisposed about said hub, each said vane having an axis passing throughsaid axis of rotation; a pair of journals, each said journal beingconnected to a respective vane and rotatably mounted in said hub torotate about said respective van axis; a connecting rod perpendicular tosaid axis of rotation and secured between and to said journals to absorbcentrifugal forces thereof; a tubular bushing surrounding said rod andholding said rod under a prestressed tension force; and a pair ofspherical bearings, each said bearing being disposed between arespective journal and a respective end of said connecting rod to permitrotation of said vanes relative to said connecting rod.
 7. A rotor asset forth in clain 6 wherein each spherical bearing has an inner ringwith a spherical surface engaging one end of said bushing and whichfurther comprises a pair of rings, each ring being threaded on arespective threaded end of said rod against a respective inner ring forprestressing of said rod.
 8. A rotor as set forth in clain 7 whereineach spherical bearing has an outer ring slidably receiving a respectiveinner ring and which further comprises a pair of threaded rings, eachsaid threaded ring being threaded into a respective journal.